There are a number of conditions that require patients to manually drain urine from the bladder at intervals, and this can be performed either under the supervision of an attending physician or healthcare worker, or on occasions can be performed by a patient themselves. One such common condition is an overactive bladder. For many conditions it is also necessary to deliver a medicament to the bladder. For this to be successful, it is important that the bladder is initially drained of any accumulated urine to prevent dilution of the medicament, so allowing a pre-determined dose to be applied. Direct application of medicaments to the interior of the bladder, known as “intravesical” administration is becoming more common, and one such specialized catheter to allow drainage and intravesical administration is described in UK patent GB 2448892. In this device, a urinary cannula is described, and that comprises a number of channels extending from a proximal to a distal end of the catheter. There is a drainage channel to allow urine to flow from one end to the other; and an instillation channel to allow medicament to be delivered from the proximal to the distal end and a control channel to allow a viscous control fluid to be delivered to a cuff located within the drainage channel. In some embodiments a further channel is provided to allow delivery of a fluid to a balloon adjacent to the external wall of the catheter, known as a Foley balloon, which may be inflated to secure the end of the catheter at the correct position in the bladder after insertion via the urethra.
Such devices are complex and expensive to manufacture, and it is an object of the present invention to provide an improved such catheter.